Square Squash YAML YAML.load deserialization

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.5$0-$5k1.63-

Summaryinfo

A vulnerability was found in Square Squash. It has been rated as critical. This vulnerability affects the function YAML.load of the component YAML Handler. The manipulation leads to deserialization. This vulnerability only affects products that are no longer supported by the maintainer. This vulnerability is traded as CVE-2026-109391. It is possible to initiate the attack remotely. There is no exploit available. It is suggested to install a patch to address this issue.

Detailsinfo

A vulnerability was found in Square Squash (version unknown). It has been rated as critical. This issue affects the function YAML.load of the component YAML Handler. The manipulation with an unknown input leads to a deserialization vulnerability. Using CWE to declare the problem leads to CWE-502. The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Square Squash through commit e73f280 contains an insecure deserialization vulnerability that allows unauthenticated attackers to store crafted YAML via the POST /api/1.0/symbolication endpoint. When occurrences referencing the attacker-controlled symbolication UUID are symbolicated, the stored values are passed to YAML.load with SafeYAML in unsafe mode, enabling arbitrary Ruby object deserialization and potential code execution.

The advisory is shared at hackmd.io. The identification of this vulnerability is CVE-2026-109391 since 10/12/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available.

Applying the patch e73f2805f9eb30780a5c213b001f0f4255660fbf is able to eliminate this problem.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 7.7
VulDB Meta Temp Score: 7.5

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 8.1
CNA Vector (VulnCheck): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Deserialization
CWE: CWE-502 / CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Patch: e73f2805f9eb30780a5c213b001f0f4255660fbf

Timelineinfo

10/12/2026 Advisory disclosed
10/12/2026 +0 days CVE reserved
10/12/2026 +0 days VulDB entry created
10/12/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: hackmd.io
Status: Confirmed

CVE: CVE-2026-109391 (🔒)
GCVE (CVE): GCVE-0-2026-109391
GCVE (VulDB): GCVE-100-416969

Entryinfo

Created: 10/12/2026 17:38
Changes: 10/12/2026 17:38 (76)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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